The Seanad Committee on Members' Interests is to hold a public hearing next Friday as part of its investigation into Senator Ivor Callely's expenses.
The Senator has been invited to give evidence to the committee.
The Dublin-based Senator stood down from the Fianna Fáil parliamentary party earlier this month after it was disclosed he made over €80,000 worth of travel and subsistence claims from his holiday home in west Cork.
A second Fianna Fáil senator, Larry Butler, has been asked to provide explanations to his party for claims that he has made.
Mr Butler had claimed expenses from Graiguenamanagh, Co Kilkenny, but was resident in Foxrock in south Dublin when he was elected to the Seanad.
Both politicians resigned the party whip earlier this month after their cases were referred to the Seanad's Members' Interests Committee.
